Laser line generating device

ABSTRACT

A laser beam generating device includes a housing a first laser diode which generates a visible first output beam which projects outside of the housing onto a surface and a second laser diode which generates a visible second output beam which projects outside of the housing onto the surface. The laser beam generating device has a first mode in which the first laser diode and the second laser diode are both on. In the first mode, the first laser diode is operated at a first duty cycle the second laser diode is operated at a second duty cycle. The first duty cycle and the second duty cycle are staggered.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/508,670 filed Jul. 11, 2019, now U.S. Pat. No. 10,989,533, which is acontinuation of U.S. application Ser. No. 15/480,469 filed Apr. 6, 2017,now U.S. Pat. No. 10,393,521, which claims the benefit of PCTApplication No. PCT/CN2016/101949 filed on Oct. 13, 2016. The entiredisclosures of the above applications are incorporated herein byreference.

FIELD OF THE INVENTION

The present disclosure relates to an improved laser line generatingdevice for assisting with construction layout tasks.

BACKGROUND

Laser line generators are commonly used for construction layout. Forexample, laser line generators may be used to partition an open space ina commercial building into useable office areas. In this example, thelaser line generator generates squared lines on a floor which are inturn used to construct walls or cubicles. At some later time, it may bedesirable to transfer the squared lines from the floor to the ceiling orfrom the ceiling to the floor. In other instances, it may be desirableto generate squared lines on the ceiling and floor simultaneously. Inany case, it is desired to provide an improved laser line generator forassisting with construction layout tasks.

This section provides background information related to the presentdisclosure which is not necessarily prior art.

SUMMARY

According to an aspect, there is a laser beam generating device whichincludes a housing, a laser light generator disposed in the housing andoperable to generate a first output beam and a second output beam, thefirst output beam and the second output beam projecting outside of thehousing. The laser light generator is configured to operate in a firstmode in which the first output beam is projected outside of the housingand the second output beam is not projected outside of the housing. Thelaser light generator is configured to operate in a second mode in whichthe first output beam and the second output beam are both projectedoutside of the housing. In the first mode, the first output beam isoperated at a first duty cycle and in the second mode the first outputbeam is operated at a second duty cycle, different than the first dutycycle.

The first output beam may be projected as a line and wherein the secondoutput beam is projected as a dot.

In the second mode at least a portion of the first output beam and thesecond output beam may overlap outside of the housing.

The first duty cycle may be higher than the second duty cycle.

The first duty cycle may be at least 10 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 15 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 20 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 25 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 30 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 35 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 40 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 45 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 50 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 55 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 60 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 65 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 70 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 75 percentage points higher thanthe second duty cycle.

The first duty cycle may be 85% or greater.

The second duty cycle may be 75% or less.

In the second mode, the first beam output and the second beam output mayhave staggered duty cycles whereby when a pulse of the first beam ishigh a pulse of the second beam is low and whereby when the pulse of thefirst beam is low, the pulse of the second beam is high.

The first output beam may be projected as a line and the second outputbeam may be projected as a dot.

In the second mode at least a portion of the first output beam and thesecond output beam may overlap outside of the housing.

The first duty cycle may be higher than the second duty cycle and thefirst duty cycle may be greater than 90%.

In the second mode, the second output beam may operate at a third dutycycle.

The second duty cycle may be less than 80%.

The third duty cycle may be less than 80%.

The laser light generator may include a first laser diode whichgenerates the first output beam and a second laser diode which generatesthe second output beam.

According to another aspect, there is a laser light generating deviceincluding a housing; a first laser diode, the first laser diode operableto generate a visible first output beam which projects outside of thehousing onto a surface; and a second laser diode, the second laser diodeoperable to generate a visible second output beam which projects outsideof the housing onto the surface. The laser beam generating device isoperable in a first mode wherein the first laser diode is on and a thesecond laser diode is off such that the visible first output beam isprojected outside of the housing and a second mode in which the firstlaser diode and the second laser diode are both on such that both thevisible first output beam and the visible second output beam areprojected outside of the housing. In the first mode, the first laserdiode is operated at a first duty cycle and in the second mode the firstlaser diode is operated at a second duty cycle, different than the firstduty cycle.

The first duty cycle may be higher than the second duty cycle.

The first duty cycle may be at least 15 percentage points higher thanthe second duty cycle.

The first duty cycle may be at least 25 percentage points higher thanthe second duty cycle.

The first visible output beam may produce a line and wherein the secondvisible output beam produces a dot.

The dot may intersect with the line.

The first visible output beam and the second visible output beam mayintersect.

In the second mode, the second laser diode is operated at a third dutycycle.

The second duty cycle and the third duty cycle are staggered.

In the second mode, the second laser diode may be operated at a thirdduty cycle, wherein the second duty cycle and the third duty cycle havethe same phase.

The laser beam generating device may further include a third mode inwhich the first laser diode and the second laser diode are both on suchthat both the visible first output beam and the visible second outputbeam are projected outside of the housing. The first laser diode may beoperated at a first frequency in the second mode. The first laser diodemay be operated in a second frequency in the third mode and the secondfrequency may be at least 20% different than the first frequency.

According to another aspect, there is a laser beam generating deviceincluding a housing; a first laser diode, the first laser diode operableto generate a visible first output beam which projects outside of thehousing onto a surface; a second laser diode, the second laser diodeoperable to generate a visible second output beam which projects outsideof the housing onto the surface. The laser beam generating device isoperable in a first mode in which the first laser diode and the secondlaser diode are both on such that both the visible first output beam andthe visible second output beam are projected outside of the housing. Inthe first mode, the first laser diode is operated at a first duty cyclethe second laser diode is operated at a second duty cycle and whereinthe first duty cycle and the second duty cycle are staggered.

High states of the first duty cycle and the second duty cycle mayoverlap less than 25% of the time.

The high states of the first duty cycle and the second duty cycle mayoverlap less than 15% of the time.

According to another aspect, there is an exemplary embodiment of a laserbeam generating device which includes a housing, a first laser diode,the first laser diode operable to generate a visible first output beamwhich projects outside of the housing onto a surface and a second laserdiode, the second laser diode operable to generate a visible secondoutput beam which projects outside of the housing onto the surface. Thelaser beam generating device has a first mode in which the first laserdiode is on and the second laser diode is off such that the visiblefirst output beam is projected outside of the housing and the visiblesecond output beam is not projected outside of the housing. The laserbeam generating device has second and third modes in which both thefirst laser diode and the second laser diode are on such that thevisible first output beam is projected outside of the housing and thevisible second output beam is projected outside of the housing. Thefirst laser diode may be operated at a first frequency in the secondmode. The first laser diode may be operated at a second frequency in thethird mode, the second frequency being different than the firstfrequency.

The second frequency may be at least 15% different (at least 15% higheror at least 15% lower) than the first frequency.

The second frequency may be at least 30% different (at least 30% higheror at least 30% lower) than the first frequency.

The second frequency may be at least 50% different (at least 50% higheror at least 50% lower) than the first frequency.

The second frequency may be at least 75% different (at least 75% higheror at least 75% lower) than the first frequency.

According to another aspect, there is an exemplary embodiment of a laserbeam generating device which includes a housing, a first laser diode,the first laser diode operable to generate a visible first output beamwhich projects outside of the housing onto a surface and a second laserdiode, the second laser diode operable to generate a visible secondoutput beam which projects outside of the housing onto the surface. Atleast one of the average or instantaneous power output of at least oneof the beams is adjusted such that a predetermined maximum average orinstantaneous (respectively) combined power output of the (at least two)beams is not exceeded.

The predetermined maximum average intensity may be 2 W/cm². Thepredetermined maximum average intensity may be 2 W/cm² and measured over2 seconds. The predetermined maximum average intensity may be 2 W/cm²and measured over 5 seconds.

The predetermined maximum average intensity may be 2.5 W/cm². Thepredetermined maximum average intensity may be 2.5 W/cm² and measuredover 2 seconds. The predetermined maximum average intensity may be 2.5W/cm² and measured over 5 seconds.

The predetermined maximum average intensity may be 3 W/cm². Thepredetermined maximum average intensity may be 3 W/cm² and measured over2 seconds. The predetermined maximum average intensity may be 3 W/cm²and measured over 5 seconds.

The predetermined maximum average intensity may be 3.5 W/cm². Thepredetermined maximum average intensity may be 3.5 W/cm² and measuredover 2 seconds. The predetermined maximum average intensity may be 3.5W/cm² and measured over 5 seconds.

The predetermined maximum average intensity may be 4 W/cm². Thepredetermined maximum average intensity may be 4 W/cm² and measured over2 seconds. The predetermined maximum average intensity may be 4 W/cm²and measured over 5 seconds.

The predetermined maximum instantaneous intensity may be 2 W/cm². Thepredetermined maximum instantaneous intensity may be 2.5 W/cm². Thepredetermined maximum instantaneous intensity may be 3 W/cm². Thepredetermined maximum instantaneous intensity may be 3.5 W/cm². Thepredetermined maximum instantaneous intensity may be 4 W/cm².

The average power output may be adjusted by varying the duty cycle of atleast one modulated beam.

The instantaneous power output may be adjusted by (at least) two beamsbeing modulated out of phase with respect to each other.

The instantaneous power output may be adjusted by there being (at least)two constant (unmodulated) beams, at least one of which is emitted atreduced power.

According to another aspect, there is an exemplary embodiment of a laserbeam generating device which includes a housing, a first laser diode,the first laser diode operable to generate a visible first output beamwhich projects outside of the housing onto a surface and a second laserdiode, the second laser diode operable to generate a visible secondoutput beam which projects outside of the housing onto the surface. Thefirst and second visible output beams overlap one another. The firstlaser diode and the second laser diode may be independently turned onand off. The laser generating device may automatically adjust the outputof at least one of the first laser diode and the second laser diode whenthey are both turned on at the same time so as to limit the intensity ofthe laser beams at the overlap.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary embodiment of a laser beamgenerating device;

FIG. 2 is an exploded view of laser modules for the exemplary embodimentof the laser beam generating device;

FIG. 3 is a perspective view of a laser assembly of the exemplaryembodiment of the laser beam generating device;

FIG. 4 is a view of a wall with intersecting laser beam lines and alaser beam dot;

FIG. 5 is a diagram of pulse-width-modulation (PWM) duty cycles fordiodes of the exemplary embodiment of the laser beam generating device;

FIG. 6 is another diagram of pulse-width-modulation (PWM) duty cyclesfor diodes of the exemplary embodiment of the laser beam generatingdevice;

FIG. 7 is a diagram of another exemplary embodiment ofpulse-width-modulation (PWM) duty cycles for diodes of the laser beamgenerating device;

FIG. 8 is a diagram of yet another exemplary embodiment ofpulse-width-modulation (PWM) duty cycles for diodes of the laser beamgenerating device; and

FIG. 9 is another diagram of the exemplary embodiment of FIG. 8 ofpulse-width-modulation (PWM) duty cycles for diodes of the laser beamgenerating device.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIGS. 1-3 illustrate an exemplary laser line generating device 10. Thelaser line generating device 10 includes a housing 11. The housing 11includes an upper housing 12 and a lower housing 14 which mate together.The housing also further includes a roll cage 19 and the housings 12, 14and roll cage 19 form a cavity. The roll cage 19 includes an opening 17through which laser beams can project. The opening is covered by atransparent member 18, such as a transparent glass or plastic. Theopening 17 may be one continuous opening or may have multiple separateparts.

A laser assembly 16, shown in FIG. 3 , is disposed in the cavity formedby the upper and lower housings 12, 14 and the roll cage 19. In anexemplary embodiment, the upper and lower housings 12, 14 are formed byinjection molding using a suitable plastic material although othermaterials are contemplated by this disclosure. The roll cage of theexemplary embodiment is formed of metal, but may also be formed of othermaterials such as a hard plastic.

As shown in FIG. 3 , the laser assembly includes a gimbal assembly 26.The gimbal assembly 26 holds a number of laser modules 20 (FIG. 2 ).Additionally, the gimbal assembly 26 is rotatable by gravity so that itlevels the laser modules 20 so that they provide horizontal and verticallines and dots. The gimbal assembly 26 may either be allowed to rotateto a level position so that it provides level horizontal and verticallines or the gimbal assembly 26 may be locked in place so that it doesnot rotate. The laser modules 20 are operable to emit planes or dots oflight through the transparent member 18.

The laser modules 20 are shown in an exploded view without the gimbalassembly 26 in FIG. 2 . As shown in FIG. 2 , there are four lasermodules 31, 41, 51 and 61. Laser module 31 includes a laser diode 32, acollimating lens 33 and a cylindrical lens 34. The laser module 31outputs a horizontal line 71. The laser diode 32 outputs a laser beam.The collimating lens 33 collimates the beam and the cylindrical lens 34converts the beam to the line output 71. The line 71 is a horizontalline when the laser generating device 10 is placed on a flat surface andthe gimbal assembly 26 reaches its level position.

Laser module 41 includes a laser diode 42, a collimating lens 43, a mask44 and a beam splitter 45. The mask 44 provides two beams from the laserdiode 42 by allowing only part of the collimated beam to pass through.The beam splitter 45 directs the two beams in opposite directionsthrough the use of a mirrored surface to produce a dot producing beam 72on one side and a dot producing beam 73 opposite the beam 72. This willcreate dots on opposite surfaces (i.e., left and right sides when thelaser line generating device 10 is placed on a flat surface and thegimbal assembly 26 is free to move to a leveled position).

Laser module 51 includes a laser diode 52, a collimating lens 53 and acylindrical lens 54. The laser module 51 outputs a vertical line 74.Laser module 61 includes a laser diode 62, a collimating lens 63, a mask64 and a beam splitter 65. The mask 64 provides three beams from thelaser diode 62 and the beam splitter 65 splits the beams to produce adownward projecting dot producing beam 75, an upward projecting dotproducing beam 76 opposite the beam 75 and a forward projecting dotproducing beam 77. This will create dots on opposite surfaces, such as afloor and a ceiling as well as a dot forward of the laser generatingdevice 10.

As will be appreciated, the beams 71, 74 and 77 will all intersect at apoint 80. Accordingly, the intensity of the three beams 71, 74 and 77will be additive at that point 80. That is, the intensity of the beamsat 80 will be greater than the intensity of any of the beams 71, 74 and77 alone. This is shown in FIG. 4 . As shown in FIG. 4 , theintersection of the beams 71, 74 and 77 produce an intensified beam atspot 80 on a wall 90.

In the laser line generating device 10 of the exemplary embodiment, theindividual laser diodes 32, 42, 52 and 62 can be turned on and offindependently. For example, only the laser diode 32 can be turned on andthe device 10 will produce only a horizontal line 71. At another time,the diode 32 and the diode 52 can be turned on and the diodes 42 and 62can remain off. In that instance, the laser line generating device 10will output horizontal line 71 and vertical line 74. Any combination ofthe laser diodes may be turned on at any particular time including anysingle diode or any combination of diodes.

When one of the laser diodes 20 are turned on, the diode is powered bypulse width modulation (PWM). With PWM, the diode is powered over acertain percentage of a cycle, called a duty cycle. If the diode ispowered continuously, the duty cycle is 100%. If the diode is poweredhalf of the time, the duty cycle is 50%. The powered state of the dutycycle can also be referred to as the high or on state and the unpoweredportion of the duty cycle can be referred to the low or off state. Thegreater the duty cycle, the greater the intensity of the beam outputfrom the laser diodes 20.

In the exemplary embodiment of the laser line generating device 10, thelaser diodes 20 may be run at different duty cycles when they are usedtogether than when they are used separately. A user may want to have aduty cycle as high as possible so that the intensity of the output beamsis as high as possible. On the other hand, the combined intensity ofmultiple output beams may create too high of an intensity. Accordingly,according to an exemplary embodiment, the duty cycles of the laserdiodes may change depending upon which of the diodes 20 are operating.In a first mode when the diode 32 is turned on to produce horizontalline 71 and the diode 62 is not turned on, the diode 32 may be run at aduty cycle close to 100%. The duty cycle may be, for example, 95% orgreater, 90% or greater or 85% or greater. In a second mode, when boththe diode 32 and the diode 62 are turned on to produce visible beams,the diodes 32 and 62 may each be run at a duty cycle of 50%, as is shownin FIGS. 5 and 6 . When the duty cycle of the diode 62 is 100% in thefirst mode and 50% in the second mode, it is 50 percentage points higherin the first mode than in the second mode. In other embodiments, theduty cycle may be 10 or more percentage points greater in the first modethan the second mode; 20 or more percentage points greater in the firstmode than the second mode; 30 or more percentage points greater in thefirst mode than the second mode; 40 or more percentage points greater inthe first mode than the second mode; or 50 or more percentage pointsgreater in the first mode than the second mode.

The duty cycles are run staggered such that when the diode 32 is powered(high) the diode 62 is unpowered (low) and when the diode 32 isunpowered (low) the diode 62 is powered (high). In this manner, theintensity of the laser output from the laser line generating device 10does not get too great at the overlapping point 80. In some embodiments,the staggered duty cycles may overlap to some extent such that both thediode 32 and the diode 62 are high at the same time or low at the sametime for a brief amount of time. The amount of overlap may be less than25% of the time or less than 15% of the time.

In this manner, the combined intensity of the laser beams (77 and 74and/or 71) at point 80 can remain at the same intensity as the intensityof the dot laser beam 77 by itself. In some examples, the combinedintensity may be slightly greater. Particularly, the combined intensityof the laser beams at the intersection 80 may be 110% or less of theintensity of the laser beam 77 run alone; 120% or less of the intensityof the laser beam 77 run alone; 130% or less of the intensity of thelaser beam 77 run alone; or 140% or less of the intensity of the laserbeam 77 run alone.

FIGS. 5 and 6 illustrate the PWM of the diodes 32 and 62 when they areboth turned on (i.e., the second mode, discussed above). As shown inFIGS. 5 and 6 , the diode 32 and the diode 62 are each operated at aduty cycle of 50% so that the diode is at a high state 50% of the time.The duty cycles are staggered such that when the diode 32 is at a highstate, the diode 62 is at a low state.

Various particular operating schemes involving changed duty cyclesdepending upon the diodes being operated (i.e., different operatingmodes) are possible. Additionally, the various operating schemes mayinclude different particular duty cycles. Several examples of operatingschemes including various modes are shown below. Each row of theexamples is considered to be one mode of the example operating scheme.

Example 1

Laser Line Generating Device 10 Visibly Diode 32 Diode 52 Diode 62Projected Beams Duty Cycle Duty Cycle Duty Cycle Line 71 projected; 100%OR  0%  0% Line 74 not Greater than 90% projected; OR Dots 75, 76, 77 -Greater than 80% not projected Line 71 not  0% 100% OR  0% projected;Greater than 90% Line 74 projected; OR Dots 75, 76, 77 - Greater than80% not projected Line 71 not  0%  0% 100% OR projected; Greater thanLine 74 not 90% OR projected; Greater than Dots 75, 76, 77 - 80%projected Line 71 projected; 100% OR 100% OR  0% Line 74 projected;Greater than 90% Greater than 90% Dots 75, 76, 77 - OR OR not projectedGreater than 80% Greater than 80% Line 71 projected; 50% 50% 50% Line 74projected; Dots 75, 76, 77 - projected Line 71 projected; 50%  0% 50%Line 74 not projected; Dots 75, 76, 77 - projected Line 71 not  0% 50%50% projected; Line 74 projected; Dots 75, 76, 77 - projected

Example 2

Laser Line Generating Device 10 Visibly Diode 32 Diode 52 Diode 62Projected Beams Duty Cycle Duty Cycle Duty Cycle Line 71 projected; 100%OR  0%  0% Line 74 not Greater than 90% projected; OR Dots 75, 76, 77 -Greater than 80% not projected Line 71 not  0% 100% OR  0% projected;Greater than 90% Line 74 projected; OR Dots 75, 76, 77 - Greater than80% not projected Line 71 not  0%  0% 100% OR projected; Greater thanLine 74 not 90% OR projected; Greater than Dots 75, 76, 77 - 80%projected Line 71 projected; 50% 50%  0% Line 74 projected; Dots 75, 76,77 - not projected Line 71 projected; 33% 33% 33% Line 74 projected;Dots 75, 76, 77 - projected Line 71 projected; 50%  0% 50% Line 74 notprojected; Dots 75, 76, 77 - projected Line 71 not  0% 50% 50%projected; Line 74 projected; Dots 75, 76, 77 - projected

Example 3

Laser Line Generating Device 10 Visibly Diode 32 Diode 52 Diode 62Projected Beams Duty Cycle Duty Cycle Duty Cycle Line 71 projected; 100%OR  0%  0% Line 74 not Greater than 90% projected; OR Dots 75, 76, 77 -Greater than 80% not projected Line 71 not  0% 100% OR  0% projected;Greater than 90% Line 74 projected; OR Dots 75, 76, 77 - Greater than80% not projected Line 71 not  0%  0% 100% OR projected; Greater thanLine 74 not 90% OR projected; Greater than Dots 75, 76, 77 - 80%projected Line 71 projected; 75% 75%  0% Line 74 projected; Dots 75, 76,77 - not projected Line 71 projected; 50% 50% 30% Line 74 projected;Dots 75, 76, 77 - projected Line 71 projected; 75%  0% 50% Line 74 notprojected; Dots 75, 76, 77 - projected Line 71 not  0% 75% 50%projected; Line 74 projected; Dots 75, 76, 77 - projected

The different modes (row) of the different examples may be interchangedor added to the different examples. For example, the mode of the lastrow of Example 3 could replace the last row of Example 2 or could beadded as an additional mode (row) to Example 3. Also, other duty cyclesare possible. For example, the duty cycle for diode 52 in the last mode(row) of Example 3 could be 80% or 70% instead of 75%.

FIGS. 5 and 6 also illustrate a burst repetition cycle 101. The burstrepetition cycle 101 is an additional feature which may be added to theabove examples. The burst repetition cycle 101 is a 100 ms cycles andincludes one pulse cycle 102. In the pulse cycle, the diode 32 isoperated at a 50% duty cycle at a high speed during one of period wherethe diode 32 would otherwise be operated at a low. The burst repetitioncycle may be used to help detect the horizontal laser line 71. In FIG. 5, only the diode 32 has a pulse cycle 102.

As shown in FIG. 6 , the diode 62 may also have a pulse cycle 103. Thepulse cycle 103 also allows for detection of the dots 75, 76 and 77. Thepulse cycle 103 is similar to pulse cycle 102 in that it is operated ata 50% duty cycle. However, the pulse cycle 103 operates at a time wherethe diode 62 would otherwise be at a low, as is shown in FIG. 6 . In theembodiment of FIG. 6 , the pulse cycles 102 and 103 can themselves bestaggered such that the diode 32 and the diode 62 are high at oppositetimes. Although diodes 32 and 62 are illustrated in FIGS. 5 and 6 , thepulse cycles may be applied to other diodes. For example, diode 52 couldsimilarly include a pulse cycle 102.

Another exemplary embodiment of different modes is shown in FIG. 7 . Asshown in FIG. 7 , when only a diode 32 is turned on creating a firstline 71, the diode 32 is run at a 100% duty cycle. Bursts 102 may alsoinclude for the diode 32 to aid in detection of the line 71 by a laserdetector. Similarly, when either the diode 52 is run by itself or diode62 is run by itself, those diodes are run at a 100% duty cycle, as shownin the top half of FIG. 7 (Mode 1). Mode 1 of FIG. 7 is shown in the tophalf of the drawing and includes the situations where one of the diodes32, 52 or 62 are run without the other two. In FIG. 7 , the diode 32 isshown as being run with bursts 102 and the diodes 52 and 62 withoutbursts. However, any of the diodes may be run with or without the bursts102.

Mode 2 of the exemplary embodiment of FIG. 7 is shown at the bottom halfof the drawing. Mode 2 is automatically entered when two or more of thediodes 32, 52 and 62 are turned on at the same time. As shown, in Mode2, the diodes are each operated at a 50% duty cycle. In the exemplaryembodiment, the diodes are operated at the same phase, rather thanstaggered. In other exemplary embodiments, the duty cycles may bestaggered. In the exemplary embodiment, when the diode 32 is operated toproject beam 71 at the same time that either one or both of the diodes52 and 62 are turned on to project the beam 74 and dot 77, the diodeswhich are turned on are operated at a 50% duty cycle at a frequency of8.3 kilohertz (kHz). Other duty cycles are also possible. For example,the duty cycle may be in the range of 40-60%; 35-65% or 30-70%.Additionally, the frequency does not have to be 8.3 kHz. The frequencymay be in a range of 7-9 kHz; 6.5-9.5 kHz; 6-10 kHz or 5-11 kHz.

Another exemplary embodiment is shown in FIGS. 8 and 9 in which thefrequency of the duty cycles change. FIGS. 8 and 9 show three (3)different modes. FIG. 8 illustrates a Mode 1 at the top half of thedrawing and a Mode 2 at the bottom half of the drawing. FIG. 9illustrates Mode 2 at the top half of the drawing and Mode 3 at thebottom half of the drawing. Mode 1 of FIG. 8 is similar to Mode 1 of theexemplary embodiment of FIG. 7 . Specifically, Mode 1 includes diodesoperating at a 100% duty cycle. The diode 32 is operated at a 100% dutycycle to project a line 71 when the diode 32 is on and the diodes 52 and62 and their respective line 74 and dots 75, 76, 77 are off. The diode52 is operated at a 100% duty cycle to project a line 74 when the diode52 is on and the diodes 32 and 62 and their respective line 71 and dots75, 76, 77 are off. Similarly, the diode 62 is operated at a 100% dutycycle to project dots 75, 76 and 77 when the diode 62 is on and thediodes 32 and 52 and their respective line 71 and 74 are off. Mode 1 ofthe exemplary embodiment of FIGS. 8 and 9 does not include any burst,though such a feature may be included in other exemplary embodiments.

Mode 2 of the exemplary embodiment of FIGS. 8 and 9 is shown at thebottom of FIG. 8 and again at the top of FIG. 9 . In mode 2, more thanone of the diodes 32, 52 and 62 are operated at the same time so thatmultiple lines or at least one line and a dot are projected such thatthey intersect at 80. In mode 2, the operating diodes are operated at a50% duty cycle at the same phase and at a frequency of 4 kilohertz(kHz). As will be appreciated, this is a lower frequency than that ofthe embodiment of FIG. 7 . In other embodiments, other frequencies arealso possible. For example, the frequency may be in a range of 3-5 kHz;2.5-5.5 kHz; 2-6 kHz or 1.5-6.5 kHz.

Mode 3 is shown at the bottom half of FIG. 9 . Mode 3 is similar to Mode2 in that the diodes are operated at a 50% duty cycle. However, in Mode3, the frequency of the duty cycle is 10 kilohertz (kHz). That is, thefrequency in Mode 3 is different than the frequency in Mode 2.Accordingly, the frequency in mode 3 is more than double the frequencyin mode 2. In various embodiments, the frequency may of mode 3 may be50% or more higher than the frequency of mode 2; 75% or more higher thanthe frequency of mode 2; 100% or more higher than the frequency of mode2; or 125% or more higher than the frequency of mode 2. Additionally,the frequency of Mode 3 in different embodiments may be different than10 kilohertz (kHz). For example, the frequency may be in a range of 9-11kHz; 8.5-11.5 kHz; 8-12 kHz or 7-13 kHz. The change in frequency betweenModes 2 and 3 allows for the lasers to be detected by a detector. Thedetector may detect a change in frequency which allows the lasers to bemore easily detected.

As can be appreciated, according to exemplary embodiments of the presentapplication, the intensity of the combined laser beams at point 80 doesnot become too high. When more than one laser beam is on such that theywould overlap at point 80, the power of one or more of the diodes can beadjusted to prevent the intensity at point 80 from exceeding apredetermined maximum intensity. The predetermined maximum intensity maybe an instantaneous maximum intensity or an average maximumpredetermined intensity measured over a short period of time. Forexample, the predetermined maximum average intensity may be 2 W/cm². Thepredetermined maximum average intensity may be 2 W/cm² and measured over2 seconds. The predetermined maximum average intensity may be 2 W/cm²and measured over 5 seconds.

The predetermined maximum average intensity may be 2.5 W/cm². Thepredetermined maximum average intensity may be 2.5 W/cm² and measuredover 2 seconds. The predetermined maximum average intensity may be 2.5W/cm² and measured over 5 seconds.

The predetermined maximum average intensity may be 3 W/cm². Thepredetermined maximum average intensity may be 3 W/cm² and measured over2 seconds. The predetermined maximum average intensity may be 3 W/cm²and measured over 5 seconds.

The predetermined maximum average intensity may be 3.5 W/cm². Thepredetermined maximum average intensity may be 3.5 W/cm² and measuredover 2 seconds. The predetermined maximum average intensity may be 3.5W/cm² and measured over 5 seconds.

The predetermined maximum average intensity may be 4 W/cm². Thepredetermined maximum average intensity may be 4 W/cm² and measured over2 seconds. The predetermined maximum average intensity may be 4 W/cm²and measured over 5 seconds.

The predetermined maximum instantaneous intensity may be 2 W/cm². Thepredetermined maximum instantaneous intensity may be 2.5 W/cm². Thepredetermined maximum instantaneous intensity may be 3 W/cm². Thepredetermined maximum instantaneous intensity may be 3.5 W/cm². Thepredetermined maximum instantaneous intensity may be 4 W/cm².

While the invention has been described by way of exemplary embodiments,it is understood that the words which have been used herein are words ofdescription, rather than words of limitation. Additionally, it isunderstood that various features of the different embodiments may becombined. Changes may be made within the purview of the appended claims,without departing from the scope and spirit of the invention in itsbroader aspects.

What is claimed is:
 1. A laser beam generating device, comprising: ahousing; a laser light generator disposed in the housing and operable togenerate a first output beam and a second output beam, the first outputbeam and the second output beam projecting outside of the housing;wherein the laser light generator is configured to operate in a firstmode in which the first output beam is projected outside of the housingand the second output beam is not projected outside of the housing;wherein the laser light generator is configured to operate in a secondmode in which the first output beam and the second output beam are bothprojected outside of the housing; wherein the first output beam and thesecond output beam overlap in the second mode; and wherein the firstoutput beam operates at a first duty cycle in the first mode; whereinthe first output beam operates at a second duty cycle in the secondmode; wherein the second output beam operates at a third duty cycle inthe second mode; wherein the third duty cycle is staggered with respectto the second duty cycle; and wherein an intensity of the combination ofthe first output beam and the second output beam at the overlap does notexceed a predetermined limit.
 2. The laser beam generating device ofclaim 1, wherein the laser light generator includes at least two laserdiodes.
 3. The laser beam generating device of claim 1, wherein thefirst output beam is projected as a vertical line and wherein the secondoutput beam is projected as a horizontal line.
 4. The laser beamgenerating device of claim 1, wherein the first duty cycle is higherthan the second duty cycle.
 5. The laser beam generating device of claim1, wherein the first duty cycle is 85% or greater.
 6. The laser beamgenerating device of claim 5, wherein the second duty cycle is 75% orless.
 7. The laser beam generating device of claim 1, wherein theintensity of the combination of the first output beam and the secondoutput beam at the overlap in the second mode is greater than anintensity of the first output beam in the first mode.
 8. The laser beamgenerating device of claim 1, wherein the intensity of the combinationof the first output beam and the second output beam at the overlap inthe second mode is 110% or less of an intensity of the first output beamin the first mode.
 9. The laser beam generating device of claim 1,wherein the intensity of the combination of the first output beam andthe second output beam at the overlap in the second mode is 130% or lessof an intensity of the first output beam in the first mode.
 10. Thelaser beam generating device of claim 1, wherein the first duty cycle isgreater than 80%.
 11. A laser level, comprising: a housing; a gimbalassembly; a first laser diode on the gimbal assembly, the first laserdiode operable to generate a first output beam which projects outside ofthe housing onto a surface; a second laser diode on the gimbal assembly,the second laser diode operable to generate a second output beam whichprojects outside of the housing onto the surface; wherein the laserlevel is configured to operate in a first mode and a second mode;wherein in the first mode the first laser diode is on and the secondlaser diode is off; wherein in the second mode both the first laserdiode and the second laser diode are on and at least a portion of thefirst output beam overlaps with at least a portion of the second outputbeam on the surface; wherein the first output beam operates at a firstduty cycle in the first mode; wherein the first output beam operates ata second duty cycle in the second mode; wherein the second output beamoperates at a third duty cycle in the second mode; wherein the thirdduty cycle is staggered with respect to the second duty cycle.
 12. Thelaser level of claim 11, wherein the first output beam is projected as avertical line and wherein the second output beam is projected as ahorizontal line.
 13. The laser level of claim 11, wherein the first dutycycle of is higher than the second duty cycle.
 14. The laser beamgenerating device of claim 13, wherein the first duty cycle is 85% orgreater.
 15. The laser level of claim 14, wherein the second duty cycleis 75% or less.
 16. The laser level of claim 11, wherein an intensity ofthe combination of the first output beam and the second output beam atthe overlap in the second mode is greater than an intensity of the firstoutput beam in the first mode.
 17. The laser level of claim 16, whereinthe intensity of the combination of the first output beam and the secondoutput beam at the overlap in the second mode is 130% or less of theintensity of the first output beam in the first mode.
 18. The laserlevel of claim 11, wherein the first laser diode is part of a lasermodule; and wherein the laser module further comprises a collimatinglens and a cylindrical lens.
 19. The laser level of claim 11, whereinthe first duty cycle is greater than 80%.
 20. A laser level, comprising:a housing; a gimbal assembly; a first laser diode on the gimbalassembly, the first laser diode operable to generate a first output beamwhich projects outside of the housing onto a surface; a second laserdiode on the gimbal assembly, the second laser diode operable togenerate a second output beam which projects outside of the housing ontothe surface; wherein the laser level is configured to operate in a firstmode and a second mode; wherein in the first mode the first laser diodeis on and the second laser diode is off; wherein in the second mode boththe first laser diode and the second laser diode are on and at least aportion of the first output beam overlaps with at least a portion of thesecond output beam on the surface; wherein the first output beamoperates at a first duty cycle in the first mode; wherein the firstoutput beam operates at a second duty cycle in the second mode; whereinthe second output beam operates at a third duty cycle in the secondmode; wherein the third duty cycle is staggered with respect to thesecond duty cycle; whereby an intensity of the combination of the firstoutput beam and the second output beam at the overlap does not exceed apredetermined limit; and wherein the predetermined limit is related toat least one of a predetermined maximum instantaneous intensity and apredetermined maximum average intensity.